The crystal and molecular structure of bis(tetracarbonylcobalt)mercury, Hg[Co(CO)4]2

The crystal structure of Hg[Co(CO)4]2 has been determined by single-crystal X-ray diffraction. The crystals are monoclinic, P21/a; a= 12·59, b= 16·44, c= 6·62 Å, β= 90° 40′, Z= 4. The molecule has approximately D3d symmetry; the carbonyl groups are staggered with respect to one another. The idealised co-ordination about the cobalt atoms is trigonal bipyramidal, but the equatorial carbonyls are bent towards the mercury atom. The Hg–Co bond lengths are 2·50 Å.